Which Came First - the Turtle or the Egg?
Enhanced Video Resource

The life cycle of a sea turtle is fascinating and mysterious.  This video from NATURE explores the role that Cuba’s beaches play in sea turtles’ lives: how they nest, how they return to the same beaches year after year, how they recognize the beach by the scent of the sand.  The video also examines the threats facing sea turtles, and the efforts Cuban biologists are taking to help them.

Discussion Questions:

  • How do you think the turtles know how to successfully navigate and return to their home beach at Cayo Largo?
  • What are the advantages of the turtles laying their eggs at night?
  • What impact does Cuba’s growing tourist industry have on the sea turtle population?
  • Why is it a problem for sea turtles to be exploited on the black market?
  • How are traditional nesting beaches affected by development and pollution?

Background Essay:

Cayo Largo is a small island in the Canarreos Archipelago, approximately 80 miles from the main island of Cuba.  There are no permanent residents of Cayo Largo – hotel and resort workers live on nearby Isla de la Juventud or the mainland.  Even the sea turtles, so dependent on the white sand beaches of Playa Sirena, visit Cayo Largo just once a year.  Three species of sea turtle return to their birthplaces on Cayo Largo between April and September each year: the hawksbill (Eretmochelys imbricata), the loggerhead (Caretta caretta), and the green turtle (chelonia mydas).  The green turtle population is the largest turtle population on the island.

The life of a green turtle is simple, but not easy.  Cuba’s turtles hatch on the beach, and dodge a variety of predators from the land and air as they make their way to the Atlantic Ocean.  Those hatchlings that make it to the sea spend as long as five years living in the open ocean, far from the shore.  As the turtles mature, they return to coastal areas, seeking out shallow, grassy waters.  Adult turtles will move even further inland, preferring inshore bays, lagoons, and shoals.  Many turtles will find one favorite spot, and travel only between that location and Playa Sirena for their entire lives.

Female green turtles return to the waters surrounding the nesting grounds at Cayo Largo once every two to four years; males make the trip every year in search of potential mates.  Once the male and female turtles mate in the water, the females climb on to the beach to create a nest in which to lay their eggs.  Forty-five to seventy-five days later, the eggs will hatch and the cycle begins anew.

Cayo Largo is the most important reproduction site for green turtles in all of the Caribbean and the Gulf of Mexico.  As a result, it is extremely important to preserve the beach conditions at Playa Sirena.  Threats to the beach include increased tourism and increased land development, both of which would reduce the amount of available land and increase the amount of artificial light, which is particularly detrimental to the adult turtles and the hatchlings.

Illegal hunting and poaching are also threatening Cuba’s sea turtle population.  Both domestically and internationally turtle meat, eggs, and shells are considered to be specialty items capable of bringing in large amounts of money on the black market.  Laws have been in place for several years banning the international trade of turtle products, and Cuba banned all harvesting of sea turtles and their eggs in 2008.  Conservationists and sea turtle hatcheries on Cayo Largo are working to preserve the hawksbill, loggerhead, and green turtle populations.

National Science Education Standards:

Life Science

Content Standard C


Human beings live within the world’s ecosystems. Increasingly, humans modify ecosystems as a result of population growth, technology, and consumption. Human destruction of habitats through direct harvesting, pollution, atmospheric changes, and other factors is threatening current global stability, and if not addressed, ecosystems will be irreversibly affected.

  • David L. Kaliner

    Preserving the natural ecology and beach conditions of Cayo Largo in the Canarreos Archipelago is essential if such species as the loggerhead, the hawksbill and the green turtle are expected to thrive. There are several factors presenting an enormous threat, such as a booming tourism industry, toxic pollution and increased land development, which must be carefully examined. Illegal hunting and poaching also endanger Cuba’s sea turtle population. Much more focus on eliminating extremely dangerous threats is necessary in order to ensure the survival of these precious creatures in such areas as the Caribbean and the Gulf of Mexico.

  • Gab

    I have to agree with David. The turtles nest on right on the crowded beaches. The team from the turtle farm work around the clock to collect the eggs and incubate them. Those guys barely get any sleep.I think help is needed. Half the island that is not developed is heavily polluted. Waste both from the nearby hotels but also whatever the sea washes ashore.

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